Have had some no shows and later find out there were so panicked or the provider was so desperate or both they were convinced they had to sign on right away or lose the spot and they didn't want to take their chances. For sure in Ontario there is going to be a lot more of that for the under age 2 group I the future.
Other no shows I have had were because they booked two visits back to back and underestimated the amount of time they would stay at first visit. But got an email the next day asking to reschedule and depends on my mood or how many others I have scheduled decide if I can slot them in or not. What works well with that is to say well I have an appoint for whatever time and then give them the half hour before for a quick look see and to pick up the forms. Lets you know if they are even remotely serious if they actually come for the short time, what time they actually do arrive and then when they are just leaving as next visit shows up puts pressure on both of them to make up their minds quickly.